1. Field of the Invention
The present invention relates to a thin film magnetic head provided with an electrically conductive bump for conductively connecting a lead conductor layer connected to a recording and playback element and an electrode pad for external connection.
2. Description of the Related Art
A thin film magnetic head is provided with a recording and playback element that reads magnetic recording information from a recording medium through the use of magnetoresistance effect and records magnetic information by applying a recording magnetic field to the recording medium. The recording and playback element includes a lower shield layer and an upper shield layer opposed to each other with a predetermined distance therebetween on a medium-facing surface. A multilayer film is disposed between the upper and lower shield layers so as to exert a magnetoresistance effect. A pair of magnetic core layers are opposed to each other with a magnetic gap layer therebetween on the medium-facing surface. A recording coil layer induces a recording magnetic field in the magnetic core layer, and the like. The recording and playback operation is performed by energization of the multilayer film and the recording coil layer through the lead conductor layer. Each of the multilayer film and the recording coil layer is provided with one pair of lead conductor layers. One end portion of the lead conductor layer is connected to the multilayer film or the recording coil layer, and the other end portion is extended to the back side in the height direction as compared with the recording and playback element so as to be connected to an external connection electrode pad through an electrically conductive bump. An insulating protective layer is disposed around the electrically conductive bump.
With respect to the above-described thin film magnetic head having the known structure, it is known that the temperature of the recording and playback element and the periphery thereof (in particular, the temperature around the coil layer) is increased during the recording and playback operation, and the recording and playback element is thermally expanded by this temperature increase so as to protrude toward the recording medium side. Furthermore, it is known that a temperature increase in an environment surrounding the thin film magnetic head also affects the protrusion of the recording and playback element toward the recording medium side. In recent years, the recording density has been increased and, thereby, the opposition distance between the recording medium and the thin film magnetic head is reduced. Consequently, a problem exist in that the recording and playback element that protrudes toward the recording medium side comes into contact with the recording medium, and the recording medium is damaged or the recording and playback element itself is damaged. In order to prevent the thermal expansion of the recording and playback element, it may be thought that the recording and playback element is formed by using a material having a small thermal expansion coefficient than ever. However, it is difficult to change the material without changing the element characteristics (see for example, to U.S. Pat. No. 6,842,308 B1 and Japanese Unexamined Patent Application Publication No. 2004-303320).